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Who’s who in the iPS cell field? In this post, I examine the people, journals, places, funding agencies, and companies that are the leaders in the iPS cell field. I start with publishing.

Last year we did a post on publishing trends in the iPS cell field. It suggested that the iPS cell field was exploding in terms of the number of papers, but that they were mostly being published in a surprisingly limited number of journals. What I’m seeing so far for 2011 also surprises me, but for different reasons.

Fewer papers. According to ISI Web of Science (see graph at left), almost 1/3 of the way through 2011 the number of iPS cell papers* is far lower than I would have expected, around only 75. While the updating system of ISI might be a bit slow, it doesn’t explain the relative scarcity of papers. If this trend continues, there will be, for the first time since their discovery in 2006, fewer papers published on iPS cells in one year than the previous year. In fact, 2011 may not have that many more iPS cell papers than 2009 did. Perhaps the exponential growth of iPS cell papers over the last 4 years couldn’t be sustained, but it is surprising that there is a good chance that the number could actually decline.

Citations per iPS cell paper in free fall. Despite the relatively low number of iPS cell papers so far in 2011, the number of citations remains at about the same level as it was in 2010. Not quite 1/3 of the way through 2011, my ISI search found more than 3,000 citations putting 2011 on track to have approximately the same total number of iPS cell citations as did 2010 (see graph to the right and below). But considering the tremendous increases in the number of iPS cell papers in 2009 and 2010, what no increase in total citations means is that the impact of each iPS cell paper is plummeting. Perhaps not surprisingly, since the field is flooded with iPS cell papers, each one is drawing far less attention. This also means that scientists are going to have a harder time separating the wheat from the chaff in the field.

More journals and more authors. In the past, the iPS cell field was dominated by surprisingly few scientists and journals. That is changing dramatically. In 2011 there is a striking increase in the diversity of authors and journals that are publishing iPS cell papers. Not surprisingly, Shinya Yamanaka, the discoverer of iPS cells, is by the far the most published iPS cell author with 24 papers total. George Daley is not that far behind with 17 papers. Otherwise there are hundreds of authors publishing on iPS cells. I think this is a good thing as the iPS cell field grows. The range of journals publishing iPS cell papers has greatly broadened, which is also a positive for the field as it matures.

Funding Agencies behind the iPS cell papers: some intriguing surprises. ISI also allows one to do searches by funding agencies. When I did this for iPS cell papers, I found that NIH (blue boxes–see figure below, which note is not a complete list) was far ahead of the pack. NIH funding was listed on 15% of all iPS cell papers (this is total, not just in 2011). CIRM (red boxes) was next with 4.8% of papers. Remarkably CIRM funds more iPS cell work here in California than most countries in the world fund. But guess which funding agency was 3rd? The National Natural Science Foundation of China was next with 2.2%. This is quite interesting and suggests iPS cell research is far more active in China than some might have thought and in total Chinese funding agencies (green boxes) supported 5% of iPS cell papers. I think this is very positive and we can expect the number of iPS cell papers from Chinese research institutes to continue to rise.

A bunch of funding agencies in Japan (purple boxes) collectively funded 8.8% of iPS cell papers, a major fraction of all iPS cell papers.

While there is some redundancy on the list that I have tried to control for (e.g. CIRM and California Institute of Regenerative Medicine), it appears that iPS cell papers have altogether been supported by hundreds of funding agencies, which I think is very exciting. My findings also give researchers some additional ideas as to where to get funding for iPS cell research.

Countries. Researchers who identify their institutions as within the U.S. and Japan publish 71% of all iPS cell papers with the U.S. publishing 46% of all iPS cell papers and Japan almost 25%. China is third with 11% and right behind is Germany with 10%.

Biotechs. By their nature, for-profit companies are more closed-mouth about their research. We know several are working on iPS cells, but it is likely that many more are doing so in private. iPierian is a company focused on iPS cell technology. Amongst other areas, iPierian is using iPS cells to study and develop therapies for neurological, cardiac, and metabolic diseases. Another company that has talked publicly about iPS cell technology and published some important findings is Advanced Cell Technology (ACT). However, it remains unclear if ACT is pursuing iPS cell-based drugs as they were focusing on ES cells, yet in 2010 they starting talking more about their IP in the iPS cell area. Nature also published a table (see it here) of companies working on iPS cells including Cellular Dynamics International, Fate Therapeutics, iPierian, andStemgent. There are certain to be far more companies in this area now.

*iPS cell papers are defined as those with one of the following phrases in their title: iPS cells, induced pluripotent stem cells, induced pluripotent, induced pluripotency

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The material on this blog is intended for educational purposes only and absolutely should not be considered medical or financial advice. The opinions here are only those of the authors and do not reflect those of the University of California, Davis.

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